Electric incandescent lamp



June 23, 1936. J BERGMANS 2,045,512

ELECTRIC INCANDESCENT LAMP Filed June 18, 1934' [VI EN 'TUR LIA-2v BERQMANS H75 7'' THRIVE Y Patented June 23, 1936 y r 2,045.512 nnsc'rarcINCANDESCENT LAMP I Jan Ber Eindhoven, Netherlanda assignor gmans, toGeneral Electric (Jompany, a corporation of New York Application'June18, 1934, Serial No. 731,148 In the Netherlands June 24, 1933 50mins.(01.17649 My invention relates to electric incandescent lamps and moreparticularly to lamps for use in vehicle headlamps.

It is desirable that the light beam projected when the lamp is used witha .reflectorwithout a configurated lens. The flutes are also arranged soas to make the bulb easy-to manufacture.

Further features and advantages of my inven- 20 tion will appear fromthe following description of a species thereof.

In the drawing Fig, 1 is a somewhat diagrammaticperspective view of alamp comprising my invention; Fig. 2 is a front view of the bulb;

5 Fig. 3 is a partial plan view of the bulb with a partial sectiontherein at the horizontal plane through the bulb axis; and Fig. 4 is adiagrammatic representation of beams producedby the lamps madeaccordingto my invention.

30 Referringto Fig. 1, the lamp comprises a base It and a-bulb l Ihaving a pair of filaments l2, l3 sealed therein and locatedsubstantially in the longitudinal axis IA of the lamp. The filament I2is disposed at the focus of the usual paraboloidal 35 reflector of aheadlamp to provide the main driving beam. An internal reflector I5 islocated below the forwardly disposed filament: It to direct the raysfrom said filament against the upper half of the paraboloidal reflectorof the headlamp 40 to provide a depressed beam.

The upper surface of the bulb II is provided with flutes it which arelocated in vertical planes I1 which have a common line of intersectioni8 45 which is perpendicular to the horizontal plane iii. The line I8 istangent to the tip 20 of the bulb ll through which the longitudinal axisl4 passes. The flutes l6 extend on each side of the bulb to planes 2|which form angles preferably of from 95 to 105 degrees with the verticalplane 22 which also intersects the line l8. That is, the angles 23-between the planes 2| and the horizontal plane is are of the magnitudeof from to 15 degrees. As many flutes are provided as 55 the manufactureof the bulb permits; for ex- -planes having ample, six per cm. of bulbperiphery, measured at the horizontal plane. I g I The lower part of thebulb is also preferably provided with fluted portions 24, 25 (Fig. 2).The flutes in the portion 24 are located in planes 5 which have a commonline of intersection 20-26 which is tangent to the bulb ii at the point20 and makes an angle 21 of from 5 to 15 degrees with the vertical plane22. The flutes in portion 25 are locateddn planes which have a commonline of intersection 20-28 which is also tangent to the bulb H at 20 andmakes an angle 29 of from 5 to degrees with the vertical plane 22.

A smooth strip 30 is preferably lefton the bulb between the upper andlower fluted portions for 15 purposes of adjust-ing the position of theinternal reflector l5 and the filaments with respect to the bulb.

The full line pattern in Fig. 4 illustrates a crosssection of adumb-bell" shaped driving beam obtained when thefllament i2 isenergized. The dotted lines indicate a beam pattern which might betermed ideal, the ends thereof being depressed below those of the fullline pattern.

What I claim as new and desire to secure by Letters Patent in the UnitedStates is:

1. An electric incandescent lamp comprising a bulb having a plurality offlutes on the suface thereof for spreading the light transmittedtherethrough, said flutes being located in planes having a common lineof intersection which is tangent t0 the bulb.

2. An electric incandescent lamp comprising a bulb having a plurality offlutes/{on the upper portion of the surface thereof located in verticala common line of intersection which is tangent to the tip of the bulband perpendicular to the longitudinal axis thereof.

3. An electric incandescent lamp comprising a bulb having a plurality offlutes on the upper 40 portion of the surface thereof lccated invertical planes having a common line of intersection which is tangent tothe tip of the bulb and perpendicular to the longitudinal axis thereof,and a plurality of flutes on the lower portion of the surface of .saidbulb when horizontally placed, the flutes on each side of said lowersurface being located in planes having a common line of intersectionwhich is tangent to the said tip of said bulb and forms an angle withthe vertical plane 5 through the bulb axis.

4. An electric incandescent lamp comprising a bulb having a pair offilaments disposed substantially in the longitudinal axis thereof and aconcave reflector disposed below one of said fllaments, said bulb whenhorizontally placed hav ing a. plurality oi. flutes on the upper portion01' the surface thereof located in vertical planes-having a common lineof intersection which is tangent to the tip .01 thebulb andperpendicular to the longitudinal axis thereof.

5. An electric incandescent'lamp comprising a bulb having .a pair offilaments disposed substantially. in the longitudinal axis thereof and aconcave reflector disposed below one or said Illa-' ments, said bulbwhen horizontally placed having a plurality'oi' flutes on the upperportion 01" said bulb, the flutes on each side of surface being. inplanes having a common line- .oi' intersection which is tangent to thesaid tip of the surface thereof located in vertical planes having acommon line of intersection which is tangent to the tip of the bulb andperpendicular to the longitudinal axis thereof, and a plurality offlutes on the lower portion of the surface of said lower;

said bulb and forms an angle with the vertical plane through the bulbaxis.

v JAN BERGMANS.

